Mechanisms and treatment of primary angle closure: a review

Angle closure can recur following peripheral iridotomy in up to 58% of cases, due to plateau iris syndrome, lens disproportion or ciliary block. Ciliary block glaucoma is an important differential diagnosis of shallow anterior chamber, angle closure and high intraocular pressure, which may occur spontaneously or following laser or surgery. Some underlying mechanisms of ciliary block glaucoma remain poorly understood but lens-ciliary body apposition and anterior hyaloid changes with increased hydraulic resistance are major pathogenic factors. An understanding of the pathogenic factors facilitates early recognition of ciliary block glaucoma, and aids a logical sequence of intervention. We review the mechanisms of post-iridotomy angle closure and propose a stepwise treatment strategy for these conditions.